[lelio]

My memory of physics is lacking: how would you control if the wheel spins one way or the other? The direction of the current? Is the wheel guaranteed to spin that way every time?

[Capitalist Eric]

how would you control if the wheel spins one way or the other?

It depends on which way current-flow goes... Reverse the positive and negative terminals on the commutator, and the mechanical force reverses.

BTW, the idiot who wrote this is obviously an idiot... There are no electric "engines." Only electric "motors." ;)

[RaceBannon]

Since wheels on the outside of the turn rotate faster than those on theinside, this would be an issue

Sounds like an induction motor of sorts, running the wheel, the flux of the stator causes electron flow in the windings of the rotor, which simulates a rotating electric field, causing initial rotation, but once the rotor starts turning, the induction motor has to become a shunt motor or something!

Could happen, it is done in washing machine motors, diode start, then allowing the rotation to generate the field to create a rotating field.

But those batteries do not stay charged forever, nor can they be recharged forever, some envromentalblist will complain how the dumps are now filled with lead plates and electrolyte!

[Banjoguy]

In all likelyhood, the motors are DC. If the motor is a DC motor, to change the direction of rotation, one simply reverses the current flow through the windings. To change the speed, one changes the line voltage.

Changing the speed and direction of AC motors is a complicated proposition, e.g. the frequency of the ac voltage determines speed, and a reverse voltage phase shift is sometimes required to get the motor going in the opposite direction.